Window is a young man from the Warrior's Village. Although he was raised in the Warrior's Village, he hates fighting and in that sense he is stubborn. Unknown to most others, he is a member of the secret Windowmakers Family and possesses the talent necessary for being the holder of the Window Rune. He joined the Toran Liberation Army due to his talent as a windowmaker and after the war, became a resident windowmaker for the Magician's Tower to fix the stained glass windows. - Blue Moon

Gameplay Information for Suikoden

How to Recruit: Speak to him in the Item Shop at Warrior's Village with the Window Rune in your inventory. He won't ask unless your Castle is at least Level 3.